The present invention relates to a ratchet tool having a pawl member with a curve surface which is matched with a recess in the head of the tool so as to provide a strong backup when outputting a large torque.
A conventional ratchet tool is shown in FIG. 1 and generally includes a head 1 with a ring member 2 rotatably received in a space 10 of the head 1. A toothed outer periphery 20 of the ring member 2 is engaged with a pawl member 3 which has a protrusion biased by a ball 13 urged by a spring 12. The pawl 3 has two tip ends and each of which has two teeth 30 for engaging with the toothed outer periphery 20 of the ring member 2. A lever 35 is connected to the pawl 3 to choose which tip end is engaged with the ring member 2. However, only two teeth 30 engaged with the toothed periphery 20 of the ring member 2 cannot provide enough backup for the ratchet mechanism. In other words, the engagement between the two teeth 30 and the ring member 2 cannot output a large torque and this restrains the use of the ratchet tool.
In accordance with one aspect of the present invention, there is provided a ratchet tool and comprising a ring-shaped head having a recess defined in an inner periphery thereof. A first passage is defined in a curve surface defining the recess so as to receive a first ball and a first spring. A ring member is rotatably received in the ring-shaped head and has a toothed outer periphery and a serrated inner periphery. A pawl is movably received in the recess and has a toothed surface. A protrusion extends from a top of the pawl. A plate has a notch for retaining the protrusion therein and two rods extend from the plate. A positioning ring is engaged with the ring-shaped head and has a slot through which the two rods extend. A lever has a head which has two holes so as to receive the two rods of the plate.
The primary object of the present invention is to provide a ratchet tool that has a larger contact area between the pawl member and the ring member.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.